This application relates generally to a turbine blade for a gas turbine engine wherein a tab structure under the platform is modified.
Conventional gas turbine engines include a compressor, a combustor and a turbine assembly that has a plurality of adjacent turbine blades disposed about a circumference of a turbine rotor. Each turbine blade typically includes a root that attaches to the turbine rotor, a platform, and a blade that extends radially outwardly from the turbine rotor.
The compressor receives intake air. The intake air is compressed by the compressor and delivered primarily to the combustor where the compressed air and fuel are mixed and burned in a constant pressure process. A portion of the compressed air is bled from the compressor and fed to the turbine to cool the turbine blades.
The turbine blades are used to provide power in turbo machines by exerting a torque on a shaft that is rotating at a high speed. As such, the turbine blades are subjected to a myriad of mechanical stress factors. In addition, the turbine blades are typically cooled using relatively cool air bled from the compressor resulting in temperature gradients being formed, which can lead to additional elements of thermal-mechanical stress within the turbine blades.
Further, because the turbine blades are located downstream of the combustor where fuel and air are mixed and burned in a constant pressure process, they are required to operate in an extremely harsh environment. Traditionally, a chromium-based coating is applied to the entire turbine blade to resist the corrosive effects associated with this harsh environment. The traditional coating protects primarily against stress corrosion in areas of low stress concentration, however, the traditional coating does not provide adequate protection against stress corrosion in areas of high stress concentration, for example, under the platform.
As such, it is desirable to provide a turbine blade that is optimized to reduce the effects of the mechanical and environmental stress factors.